青少年骨性Ⅱ类错▉畸形上颌后牙区微种植体植入的安全性探讨

目的: 运用锥形束CT（cone-beam CT,CBCT）测量分析骨性Ⅱ类错青少年上颌第二前磨牙与第一磨牙之间不同截面的最小根间距及颊侧骨皮质表面与根间最窄处距离,为临床上微种植体的安全植入提供参考。方法: 选取44例骨性Ⅱ类错青少年患者的CBCT资料,其中,男23例,女21例,平均年龄14.07岁。取上颌第二前磨牙与第一磨牙根间的9个水平截面,每个截面相距1 mm,分别测量每个截面的最小根间距及颊侧骨皮质表面与根间最窄处距离。采用SPSS 20.0 软件包对测量结果进行统计学分析。结果: 每个截面最小根间距和颊侧皮质骨表面与根间最窄处的距离,男女之间无显著差异（P>0.05）,左右两侧无统计学差异（P>0.05）;左侧根尖部的骨皮质表面与根间最窄处距离,与SNA角呈正相关关系;最小根间距离由釉-牙骨质界（cementoenamel junction,CEJ）至根尖逐渐增大,各截面的颊侧皮质骨表面与根间最窄处距离的均值均大于5 mm。结论: 经CBCT获取了骨性Ⅱ类错青少年上颌第二前磨牙与第一磨牙之间各截面最小根间距和颊侧骨皮质表面与根间最窄处距离,了解了其分布规律,为临床上微种植体的安全植入提供了参考。     

Distal movement of maxillary molars using a lever-arm and mini-implant system

Recently, many studies have been reported on distal molar movement using temporary anchorage devices. However, the side effects of distal movement, such as distal tipping, rotation, or extrusion, are still unsolved. This article describes the use of the lever-arm and mini-implant system for controlled distal movement of maxillary molars and two clinical cases in which patients were treated with this system. Mini implants are needed to control the point of force application in the posterior area with no anchorage loss. When the length of the lever arm and the position of the mini implant are adjusted, the desired line of action of the distal force is determined with respect to the center of resistance of maxillary molars. The lever-arm and mini-implant system is useful not only for absolute anchorage, but also for three-dimensional control during distal movement of the upper molars.     

上颌后牙缺失患者上颌窦影像学特征分析

目的：分析上颌后牙缺失患者的上颌窦影像学特征,探讨不同类型上颌后牙缺失患者上颌窦影像学的变化特点。方法：选取上颌后牙缺失患者的700份数字化X线曲面断层片作为研究资料。调查上颌窦分隔和上颌窦囊肿的发生率并根据患者的性别,年龄及缺牙状况进行分组,测量各组缺牙区的窦嵴距及窦底高度,使用SPSS16.0软件对数据进行统计学分析。结果：单牙缺失组窦嵴距〉多牙缺失组窦嵴距,两组之间差异有显著性（P〈0.001）。多牙缺失组窦底高度〉单牙缺失组窦底高度,两组之间差异有显著性（P=0.014）。59岁～77岁组女性窦嵴距〈男性窦嵴距,男性窦低高度〈女性窦低高度,组内比较有显著差异（P〈0.001）。上颌窦分隔发生率为27%,上颌窦囊肿发生率为4.9%。结论：上颌后牙缺失不同缺牙状况窦底高度和窦嵴距有统计学差异,59～77岁年龄段窦底高度和窦嵴距有性别差异。     

微型种植体支抗压低上前牙的临床应用

目的观察微型种植体支抗压低上前牙的临床疗效,评价其压低上前牙的有效性。方法选择6例高角或高角倾向伴前牙Ⅲ°深覆,上颌前部牙槽发育过度,上唇与上前牙关系严重不调的患者,平均年龄24.4±1.4岁,采用微型种植体作支抗,在两侧上侧切牙牙根和尖牙牙根间牙槽骨唇侧植入,每侧以50克的牵引力压低上前牙。测量治疗前后X线头颅定位侧位片,包括6-PP距的改变量、上中切牙压低量和转矩改变量。结果6-PP距的变化均值为0.27±0.05mm,无统计学意义(P>0.05),上中切牙平均压低6.12±0.16mm,临床牙冠平均缩短0.66±0.05mm。治疗过程中微型种植体无松动和脱落。结论用微型种植体作支抗压低上前牙,操作简单,异物感不明显,上前牙明显压低,效果良好。     

微种植体支抗压低上前牙的Typodont实验研究

目的在Typodont模型上,模拟临床应用微种植体支抗压低上前牙的过程,研究不同部位支抗对上前牙压低效果的影响。方法制作上前牙槽骨垂直发育过度的标准Typodont模型42个,随机分为ABC三组,每组14个。A组在中切牙间植入微种植体,B组在中切牙和侧切牙间植入微种植体,C组在侧切牙和尖牙间植入微种植体,应用镍钛螺簧施0．98N（100g）力压低上前牙。应用三维坐标测量仪测量牙齿标记点的三维位置并获得点云数据,Imageware12软件测量牙齿的压低量及唇（颊）倾斜度,并同时拟合牙弓曲线,研究牙弓及[牙合]平面的变化。结果①三组中上前牙均有不同程度的压低（0．9220mm±0．3037mm～5．2354mm±0．9620mm）,中切牙的压低量〉侧切牙〉尖牙,微种植体的位置越靠前,压低效果越明显。②所有牙齿均向前移动,上前牙有不同程度的唇倾,微种植体的位置越靠后,牙齿向前移动越少,唇倾越少。③微种植体的位置越靠后,牙弓及[牙合]平面的变化越小。结论①应用微种植体支抗可以有效地压低上前牙,上磨牙并未伸长。②微种植体的位置越靠后,上前牙的压低量越小,唇倾越少,牙弓变化及[牙合]平面角减少的趋势越小。反之亦然。     

Reliability of a method for the localization of displaced maxillary canines using a single panoramic radiograph

The present study was initiated to determine the validity and reproducibility of a method previously reported for localization of displaced maxillary canines by panoramic radiographs. Eleven dental specialists (five orthodontists, five surgeons, and one radiologist) and five (final year) dental students were asked to interpret initial panoramic radiographs of 20 patients with 26 unerupted canines. The method contends that, provided that the radiographic image of the unerupted canines superimposes on the root of the lateral incisor at a height coronal to the apical third, a ratio between the widest mesiodistal dimension of the affected canine and the homolateral central incisor [Canine-Incisor Index (CII)] of more than 1.15 indicates palatal displacement. Among the observers, the measurement error was small, insufficient to cause overlap between the ranges of values for the CII of buccal and palatal canines. Inter-observer reproducibility was high. Without exception, all observers correctly diagnosed the location of each of the impacted canines. The CII cut-off point of 1.15, which was arbitrarily chosen in the previous work, was shown to be valid to differentiate buccal from palatal displacement. The present method is rapid, simple, accurate, and easily taught to dental students or dental specialists, with the simplest of initial instruction. While confirmations with other radiographic techniques is strongly advised before a definitive treatment is undertaken, this method has merit in providing more information than has been available from the panoramic radiograph hitherto, to satisfy the needs of an initial orthodontic consultation.     

应用微种植体支抗压低上前牙改善露龈笑的临床研究

目的 探讨上颌前牙区微种植体支抗压低上前牙改善露龈笑的临床疗效。方法 选择露龈笑伴深覆患者15例,平均年龄（19.7±5.4）岁,在位于12,22近中根尖处颌骨内各植入1颗微种植钉,在方丝12,22近中置游离拉钩,向微种植钉做弹性牵引,每侧加力0.6 N,平均加力压低的时间为(6.2±1.6)个月。测量矫治前后X 线头颅侧位片的相关软硬组织指标,使用SPSSl3.0 软件进行统计分析。结果 前牙垂直压低的量及切牙牙冠长度明显减少（P＜0.01）,磨牙伸长量不显著。前牙的覆与覆盖均矫治达到正常范围。结论 微种植体做支抗压低上前牙、纠正深覆效果理想,能有效改善露龈笑。     

上颌后牙缺失病人上颌窦CBCT影像学特征分析

目的:针对上颌后牙缺失病人的CBCT资料,分析上颌窦内异常影像的发生率,为病人行种植术前的评估提供参考。方法:选择2011-01—03因上颌后牙缺失需行种植修复病人的CBCT资料76例,共152个上颌窦。由两名研究人员对影像资料进行观察分析,影像诊断结果分为5类:①未见异常影像;②窦底黏膜增厚;③上颌窦囊肿;④上颌窦炎;⑤上颌窦分隔。同时测量所有窦底黏膜增厚病例的平均厚度以及缺牙区窦嵴距,使用SPSS 16.0软件进行统计分析。结果:152例上颌窦中未见异常影像者65例(42.76%),黏膜增厚者36例(23.68%),上颌窦囊肿23例(15.13%),上颌窦炎17例(11.18%),上颌窦分隔11例(7.24%)。窦底黏膜增厚厚度为(3.65±1.65)mm,缺牙区窦嵴距为(7.05±2.99)mm。结论:上颌窦异常影像诊断发生率最高者为窦底黏膜增厚,其次为上颌窦囊肿;不同上颌窦影像诊断类型间窦嵴距的差异无统计学意义(P>0.05);不同性别及不同缺牙情况下诊断类型的发生率间差异无统计学意义(P>0.05)。     

CT analyses of the location of the maxillary third molar in relation to panoramic radiographic appearance

Objective  

We compared the relationship between anatomical structures analyzed by panoramic radiographs and CT images of uninfected impacted maxillary third molars and investigated the pathway of infection originating from pericoronitis of maxillary third molars.     

微小种植体支抗远移上颌磨牙的临床应用

目的:观察微小种植体作为强支抗远移上颌磨牙的作用及效果.方法:选取安氏Ⅱ类错(牙合)患者16 例,在上颌颊侧牙槽骨内共植入微小种植体22 颗,利用微小种植体做为支抗推磨牙向远中.拍摄磨牙移动前后的X线头影测量片,记录上颌磨牙及切牙移动情况,并进行统计分析.结果:利用微小种植体远移磨牙4～8 月后,所有病例磨牙达到中性关系.磨牙平均移动4.71 mm(P<0.01),上颌中切牙平均舌向移动2.16 mm(P<0.05);磨牙伸长、颊移、远中倾斜及上切牙伸长无统计学意义.结论:微小种植体可作为绝对强支抗,有效地整体远移上颌磨牙,特别适用于安氏Ⅱ类成人错(牙合)的矫治.     

微型种植体支抗压低犬上切牙的牙根表面扫描电镜观察

目的:利用微型种植体作为支抗,建立犬上切牙压低移动的实验动物模型,研究压低移动牙牙根表面结构的变化。方法:9只犬随机分为5组,其中Ⅰ组为对照组,1只犬,未施加牵引力;Ⅱ、Ⅲ、Ⅳ、Ⅴ组每组2只,在上颌两侧第二切牙牙根和第三切牙牙根之间唇侧的牙槽间隔处植入微型种植体作为支抗,每侧施加100g的牵引力,压低上颌两侧第一切牙和第二切牙,分别于加力后1、2、4、12周(主动加力4周,撤力后保持8周)时处死动物,完整拔出实验牙,制作扫描电镜标本,观察其牙根表面形态的变化。结果:Ⅱ组在牙根尖表面可见小的吸收陷窝,较浅,面积局限;Ⅲ组在接近根尖1/3处可见融合的吸收陷窝,未见牙本质暴露;Ⅳ组在根尖1/3与根中1/3交界处可见吸收深达牙本质的陷窝,且面积广泛;Ⅴ组牙根吸收停止,吸收凹陷变浅,底部变平。结论:在持续的压低力作用下,随着施力时间的延长,牙根的吸收由根尖部向牙颈部扩展,且逐渐加重。停止加力后,吸收牙根明显修复。     

Dimensional accuracy of acrylic resin maxillary denture base polymerized by a new injection pressing method

The purpose of this study was to confirm the dimensional accuracy of a newly developed injection pressing method for resin polymerization by making use of the internal electric resistance of resin to determine the optimal timing for resin injection. A new injection pressing polymerization pot with a built-in system to measure the internal electric resistance of resin was used for resin polymerization. Fluid-type resin was injected into the mold of a maxillary complete denture base under nine different conditions: three different timings for resin injection according to the electric resistance of resin dough (early stage: 11 Mohms; intermediate stage: 16 Mohms; final stage: 21 Mohms) and three different motor powers for resin injection (2000 N, 4000 N, and 6000 N). In the best polymerization condition (injected during the early stage of resin dough under a motor power of 6000 N), the adaptation of the denture base showed a statistically significant improvement compared with the conventional pouring method.     

片段隐形矫治器结合微种植体内收上前牙的临床研究

目的评估片段隐形矫治器结合微种植体矫治前突患者时对上前牙垂直向和转矩方面的控制效果。方法选取12例双牙槽前突患者,通过测量治疗前后X线头颅定位侧位片上颌前牙矢状向与垂直向的变化值,以及模型上的转矩变化值,使用SPSS 20.0软件进行统计分析。结果治疗后上切牙切缘至腭平面距离U1E-PP增加0.78 mm,上切牙根尖点至腭平面距离U1AP-PP减小0.29 mm,上切牙阻抗中心至腭平面距离U1CR-PP的变化无统计学差异(P>0.05),上切牙阻抗中心的位置基本不变;治疗后的上前牙转矩值减少,尖牙出现直立趋势。结论片段隐形矫治技术治疗前突患者对其上前牙的垂直向和转矩控制较好,总体获得了良好的治疗效果,并且在治疗期间充分发挥了隐形、美观的矫治效果。     

A method of correcting the posterior palatal seal area of a maxillary complete denture.

A processing technique for correcting the posterior palatal seal area of a maxillary denture has been described. The proper extension and displacement necessary for peripheral seal is reestablished without creating changes in occlusion or esthetics. Since the technique involves heat processing, the same acrylic resin present in the original base may be used, which makes the correction virtually impossible to detect.